1. Field of the Invention
The present invention relates to controlling the power consumption of a storage system having a plurality of storage devices therein.
2. Background of the Invention
In recent years, computerization has proceeded, and management of enormous amounts of data has come to be required. Accompanying this, there have been advances in increasing the capacity of storage systems.
One method of increasing the capacity of a storage system is to increase the number of storage devices installed therein. Examples of storage devices are disk devices (e.g. hard disk drives). However, a large amount of power is consumed in rotating a disk, and hence upon increasing the number of disk devices, the overall power consumption of the storage system increases. There are thus increased running costs, and in some cases, large-scale equipment investment may be necessary (e.g. it may be necessary to make increases in a power distribution panel in a building in which the storage system is installed).
Means for saving on power consumption are thus required. Known art for saving on power consumption includes Japanese Patent Application Laid-open No. 2000-293314 (hereinafter “document 1”) and Japanese Patent Application Laid-open No. 2000-149383 (hereinafter “document 2”).
According to the art disclosed in document 1, for a storage system, after access from a host device has ceased and a predetermined time has elapsed, control of disk device power saving is carried out (through selection of power supply on/off or a power saving mode). Moreover, in the case that there is access from the host device, if the power supply of the disk device to be accessed is off, then the power supply of that disk device is turned on, and then the access is carried out.
According to the art disclosed in document 2, a microprocessor in a storage system monitors the current capacity used during spindle startup of each of groups of disk devices, and upon detecting that the current consumption has increased, cancels spindle startup for disk devices, thus carrying out control such that the current consumption is not more than a threshold value.